Flow divider

ABSTRACT

A low divider has an inlet port, a pair of outlet ports, and a control chamber therein. The control chamber is separated by a diaphragm into a pair of sub-chambers. Restriction orifices are provided between the inlet port and the pair of sub-chambers and valve seat members are provided between the pair of sub-chambers and the outlet ports and have throttling effects between the valve seat members and the diaphragm.

United States Patent Narumi 1451 Apr. 24, 1973 1541 FLOW DIVIDER 1993,790 3/1935 Kinsella ..137 1o1 x 2,992,652 7/1961 Fellberg ..l37/1 I8 [75] Inventor Tadataka Narum" Kanya Japan 3,010,469 l1/196l Leighton ..137 1 18 [73] Assignee: Toyoda Machine Works, Ltd., v

Kariywshi, Aichbken, Japan FOREIGN PATENTS OR APPLICATIONS 22 i F 3 1971 539,895 9/1941 Great Britain ..l37/l 18 536,300 ll/l955 Italy ..l37/-lOl [21] Appl. No.: 112,233

Primary ExaminerMartin P. Schwadron [30 Foreign A li ation Prio it D t Assistant Examiner -David J. Zobkiw I Att0rney-Woodhams, Blanchard and Flynn Feb 7, l970 Japan ..45/l092() I 52 us. c1 ..137/101, 137/118 [57] ABSTRACT [51] Int. Cl. ..G05d 11/00 A low divider has an inlet port, a pair of outlet ports, [58] Field of Search ..l37/98, I00, 101, and a control chamber therein. The control chamber 1 108 is separated by a diaphragm into a pair of sub-chambers. Restriction orifices are provided between the References Cited inlet port and the pair of sub-chambers and valve seat members are provided between the pair of sub-cham- UNITED STATES PATENTS bers and the outlet ports and have throttling effects 2,283,266 5/1942 Kinsella ..l37/ 101 between the valve seat members and the diaphragm.

353,704 l2/l886 Nash ...l37/98 X 1,780,589 1 H1930 Hendrix ..l37/98 X 4 Claims, 2 Drawing Figures 9 i g llO 1,! 3 f 101 IO5 lOlO 27v 1 NH, (H7

102 j 103 I04 1 |4l 1 125 142 1. 11; "f 121 1' {1819 Y 7 I040 X2? 1114b -lO6o 1651) 1040 134 iii I36 I30 138 J J Patented April 24, 1973 2 Sheets-Sheet 2 INVENTOR. K TA 0/? mm A/APUM/ FLOW mvnmn BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to flow dividers designed to distribute the pressure fluid discharged from a fluid pressure source to a pair of pressure sensitive apparatuses or hydraulic motors.

It is an object of this invention to provide a flow di- 1 ratio, irrespective of changes in the pump discharge or the load pressure of the two pressure sensitive apparatuses or hydraulic motors.

It is another object of this invention to provide a flow divider which is capable of performing an accurate distributing function for a long period of time by maintaining the amount of flow of the pressure fluid distributed to said two pressure sensitive apparatuses or hydraulic motors always equal or at a predetermined flow ratio by means of a displacement of a. diaphragm, despite changes of the load pressure.

2. Description of the Prior Art A conventional flow divider has structure for controlling the amount of distributed flow by means of a spool which slides, in response to differential pressure, within a cylinder formed in the flow divider casing. Such a structure is costly, because high precision is needed in making said spool in order to prevent leakage of the pressure fluid into a passage perforated in the cylinder or spool. Besides, the spool responds at slow speed when a differential pressure develops within the cylinder. Therefore, it has been impossible to perform an accurate control function with conventional flow dividers. In addition, they have been unable to stand long use because of such troubles as penetration of dirt, which is entrained in the pressure fluid, into the clearance space between the inner surface of the cylinder and the spool, which dirt prevents smooth sliding of the spool, the occurrence of leakage as a result of abrasion deformation, and the like.

This invention relates to flow dividers which are capable of eliminating such defects and providing an accurate and highly sensitive control for a long period of time through the employment of a diaphragm. This invention will now be illustrated by the following embodiments in connection with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the appended drawings:

FIG. 1 is a cross-sectional view of an embodiment of this invention; and

FIG. 2 is a cross-sectional view of another embodiment of this invention.

DETAILED DESCRIPTION Referring to FIG. 1, there is shown a flow divider casing 1 having a cylindrical bore 1a therein. Disc members 4 and 6 are retained within the bore la by a snap ring 2 and a circular closure member 3 which is threaded into the casing l. Sealing rings and 16 are provided in peripheral grooves in the disc members 4 and 6. Disc members 4 and 6 have complementary recesses 4a and 6a in their opposing surfaces. A flexible diaphragm 5 is gripped at its peripheral edge between Moreover, in the flow divider casing 1, there is pro-- vided an axial passage 8 connected to the port 7 and 0 having branch passages 9 and 10 which communicate with the outer periphery of the disc members 4 and 6, respectively. On the outer periphery of the disc members 4 and 6 are formed annular grooves 11 and 12 connected with the branch passages 9 and 10, respectively. Radial passages 13 and 14 extend between and communicate with the chambers 25 and 26 and the annular grooves 11 and 12, respectively. Restriction orifices l7 and 18 having a suitable throttling effect are fitted in the passages 13 and 14 at the locations where they open into the chambers 25 and 26.

Axially extending outlet ports 19 and 20 are provided in projections 4c and 60 formed at the approximately central parts of the disc members 4 and 6. The pressure fluid which is supplied into the chambers 25 and '26 from the intake port 7 through the passages 8, 13, and 14 and orifices 17 and 18, flows out through the outlet ports 19 and 20. These outlet ports 19 and 20 communicate with passages 21 and 22 formed in the projecting parts 4b and 6b at the center of the recesses 4a and 6a of the disc members 4 and 6, respectively. Valve seat members 23 and 24 having suitable throttling effects are fitted between the passages 21 and 22 and the chambers 25 and 26.

The diaphragm 5 is formed of an elastic material such as rubber and thin steel sheets 5a and 5b are attached to both sides of its central portion for preventing deformation thereof. The diaphragm 5 is located between the orifices 17 and 18 and valve seat members 23 and 24, respectively. Therefore, the diaphragm 5, being maintained in a stabilized state, may be moved in a substantially axial direction in response to a change of the relative load pressures developed at the outlet ports 19 and 20 to control the clearances between the diaphragm 5 and the valve seat members 23 and 24 in such a manner as to maintain equal the pressure in the chambers 25 and 26, thereby distributing equally the pressure fluid supplied from the intake port 7 to the outlet ports 19 and 20.

The members of the pair of orifices 17 and 18 and, also, the pair of valve seat members 23 and 24, are formed of the same construction, respectively, and are located symmetrically with respect to the diaphragm 5, and the members of each pair have throttling effects of equal ratio. Therefore, the pressure fluid supplied from the fluid pressure source is divided in the same fluid flow ratio.

Now the operation of the flow divider of the abovementioned structure will be explained. The pressure fluid supplied from the fluid pressure source, not shown, into the flow divider assembly through the intake port 7 passes through the passage 8 to the branch passages 9 and 10. The pressure fluid divided by the branch passages 9 and 10 flows into the passages 13 and 14 by way of the annular grooves 11 and 12. The divided fluid, whose pressure is decreased as it passes through-the orifices 17 and 18, flows into the chambers 25 and 26 and thence into the passages 21 and 22 through the clearances between the diaphragm 5 and the valve seat members 23 and 24, respectively, and then the pressure fluid is discharged from the flow divider assembly through the outlet ports 19 and 20. These outlet ports 19 and may be connected with a power steering mechanism and a power brake mechanism, in the case of automobiles, for example.

When both of such mechanisms connected with the outlet ports 19 and 20 apply no pressure load on the diaphragm 5, said diaphragm is held in such a state that the pressures acting upon the right and left sides of the diaphragm 5 are equal, or, in other words, in a position where the internal pressures within the chambers and 26 are equal, and thereby the pressure drops across the orifices 17 and 18 are also equalized to discharge an equal amount of fluid from the outlet parts 19 and 20 respectively. When a pressure load is applied on the side of the outlet port 19, the pressure fluid is prevented from flowing smoothly out of this outlet port 19, which increases the pressure within the valve seat member 23, thereby moving the diaphragm 5 to the right in FIG. 1 and causing it to approach the valve seat member 24 to limit the amount of fluid flow into the valve seat member 24. Thus, the pressure within the chamber 26 is increased. Although the pressure in the valve seat member 23 is higher than that in the valve seat member 24, as the diameter of the diaphragm 5 is sufficiently larger than those of the valve seat members 23 and 24, the diaphragm 5 is pressed back leftwardly so as to decrease the pressure in the chamber 26. Thus, the diaphragm 5 is brought to a halt at an equilibrium position where the pressure in the chamber 26 is almost equal to that in the chamber 25. Therefore, the pressure drops across nozzles 17 and 18 are almost equal, and, accordingly, almost the same quantity of pressure fluid is discharged from the outlet ports 19 and 20 on the right and left hand of the flow divider assembly. But, because there is a somewhat larger fluid pressure drop across the orifice 17 than the orifice 18, the amount of fluid flow out of the outlet port 19 is a little larger than that from the outlet port 20. However, it is desirable for a distributing valve which is used, particularly, for automobiles to send a little larger quantity of fluid to the mechanism connected to the loaded side.

On the other hand, if the outlet 20 is connected to the load, the apparatus will act in the opposite sense.

ln the above-mentioned flow divider according to this invention, the fluid flow supplied from the fluid pressure source is divided into two branches having the same fluid flow. However, the fluid flow may be divided in any desired ratio by changing the dimensions of the orifices 17 and 18.

H6. 2 illustrates another embodiment of a flow divider which, though based on the same principle, is so designed as to compensate for the distribution error of the main control chamber by means of a sub-control chamber provided in front of the main control chamber. In addition, the cross-sectional areas of the orifices and valve seat members of this apparatus vary from right to left respectively, so that the amount of fluid flow may be proportioned at such a ratio as 4 to 1, for example.

Between a snap ring 102 and a closure member 103 located at opposite ends ofa cylindrical bore 101a in a flow divider casing 101 there are inserted and tightly held a disc member 104 having a recess 104a, a flexible auxiliary diaphragm 105 held on both sides of its peripheral edge by spacers 127 and 128, a disc member 106 having recesses 106a and 106b on opposite sides, a flexible main diaphragm 107 held on both sides of its peripheral edge by spacers 129 and 130, and a disc member 108 having a recess 108a, these parts being arranged in the stated order from the side of the snap ring 102. Sealing rings 115, 116 and 117 are provided in peripheral grooves in the disc members 104, 106 and 108, respectively. The recesses 104a and 1060 define an auxiliary control chamber 143 which is separated by the auxiliary diaphragm 105 into sub-chambers 131 and 132. The recesses 106b and 10811 define a main control chamber 142 which is separated by the main diaphragm 107 into sub-chambers 140 and 141. The main and auxiliary diaphragms 107 and 105 are made of resilient materials, such as plastic or metal sheets.

The flow divider casing 101 is provided with an intake port 109 and an outlet port 110, which communicate with annular grooves 111 and l 12 formed on the outer periphery of the disc member 106. From these annular grooves 111 and 112 extend radial passages 113 and 114 which communicate with the chambers 132 and 140. A restriction orifice 118 and a valve seat member 119 having suitable throttling effects are fitted in the passages 113 and 114, respectively, at the positions where they open into the chambers 132 and 140. Furthermore, below the orifice 118 there is provided an axial passage 120 connecting the chambers 132 and 140.

At the approximate centers of the projections 104c and 108a formed on the outer sides of the disc members 104 and 108 there are provided an axial inlet port 121 and an axial outlet port 124, respectively. The ports 121 and 124 communicate through passages 122 and 125 with chambers 131 and 141. A restriction orifice 123 and a valve seat member 126, both having suitable throttling effects, are fitted in the passages 122 and 125 for cooperation with the auxiliary diaphragm 105 and main diaphragm 107 respectively. In addition, on the outer peripheries of the disc members 104 and 108 there are formed annular grooves 133 and 135 which communicate with the chambers 131 and 141 through passages 134 and 136 respectively. The flow divider casing 101 is perforated with branch passages 137 and 138 which communicate with the annular grooves 133 and 135, and with each other by means of a passage 139 also formed in the casing 101. The crosssectional areas of the orifices 123 and 118 and valve seat members 119 and 126 are respectively so proportioned as to divide the amount of pressure fluid to be discharged out of the outlet ports 110 and 124 in a predetermined ratio, and therefore the pressure fluid discharged out of the flow divider assembly from the outlets 110 and 124 are divided in a ratio of, for example, 4 to 1.

Now the operation of the flow divider of the abovementioned structure will be explained. The pressure fluid supplied from the fluid pressure source, not shown, flows into the flow divider assembly through the intake ports 109 and 121. The pressure fluid coming in from the intake port 109 flows into the passage 113 by way of the annular groove 111, and then into the chamber 132 through the orifice 118. The fluid, whose pressure is decreased, flows through the clearance between the orifice 118 and the auxiliary diaphragm 105, and thence into the chamber 140, by way of the passage 120. The fluid, whose pressure is further decreased, flows through the clearance between the valve seat member 119 and the main diaphragm 107, thence to the outlet port 110, by way of the valve seat member 119, passage 114 and annular groove 112, from whence it is discharged out of the flow divider assembly into load means. The pressure fluid flowing from the intake port 121 into the flow divider assembly passes through the passage 122, to decrease the pressure thereof, thence through the clearance between the orifice 123 and the auxiliary diaphragm 105 into the chamber 131. The fluid flows into the branch passage 137 through the passage 134 and annular groove 133, and then it flows into the chamber 141 by way of the passage 139, branch passage 138, annular groove 135 and passage 136. Then, the fluid, whose pressure is further decreased, flows through the clearance between the valve seat member 126 and the main diaphragm 107, and reaches the outlet port 124 by way of the passage 125, from which the fluid is discharged out of the flow divider assembly into load means. Thus, the pressure fluid discharged out of the outlet ports 1 and 124 are proportioned in a predetermined ratio, such as 4 to 1, for example, in accordance with the ratio of the sectional areas of the orifices 123 and 118 and valve seat members 119 and 126, respectively.

The above-mentioned operation is exhibited in the no-load condition. If pressure load is applied on the side of the outlet port 124, however, it will prevent the smooth flowing of the pressure fluid 'out 6f the outlet port 124, which increases the pressure within the valve seat member 126, thereby making the main diaphragm 107 bend in a bowed or circular form in the direction to decrease the clearance between itself and the valve seat 119 (i.e. to the left in FIG. 2) to restrict the amount of the pressure fluid flowing into the valve seat member 119 to restrict the increase of the amount of the pressure fluid discharged out of the non-loaded outlet port 110. It also increases the clearance between the diaphragm 107 and the valve seat member 126 to restrict the decrease of the amount of the pressure fluid discharged out of the loaded outlet port 124. The main diaphragm 107 controls the amount of fluid flow by means of such a displacement as to make up the difference of pressure between the chambers 140 and 141 in the above-mentioned function, but it cannot adjust the pressure difference accurately, because of the existence of the restitution force of the main diaphragm 107. In order to make up this error, the auxiliary diaphragm 105 is made to bend in a bowed or circular form in a direction (i.e. to the right in FIG. 2) to reduce the clearance between itself and the orifice 118, because the pressure rise within the chamber 132 increases more than that of the chamber 131. And thereby it controls the amount of fluid flow which flows from the orifice 118 into the chamber 132. Thus, an error due to the displacement of the main diaphragm 107 is made up by the displacement of the auxiliary diaphragm 105, and properly adjusted pressure fluid is distributed from the outlet ports 110 and 124. And if load is connected on the side of the outlet port 1 10, the

auxiliary diaphragm will act in the opposite way to make up the error due to the restitution force of the auxiliary diaphragm 105.

As described above, this invention makes it possible to obtain a prompt response characteristic which can perform accurate distribution control with a flow divider which distributes the pressure fluid discharged out of the fluid pressure source evenly or in a predetermined flow ratio by means of the passage, orifices and valve seat members, because of its structure which is so designed as to maintain the amount of flow distributed from each outlet port to each subsequent means at a predetermined ratio by means of the displacement of the diaphragm in accordance with the changes of the load pressure acting upon each outlet port. ln addition, as compared with the conventional spool-type flow dividers, this divider cannot only be manufactured easily but also ensures the performance of long and effective distribution functions, since it has eliminated various troubles through the elimination of the sliding parts.

What is claimed is: i

1. A flow divider having at least one inlet zone and first and second outlet ports, comprising:

a casing; first, second and third disc members mounted in said casing, said first and second disc members defining a main control chamber, said second and third disc members defining an auxiliary control chamber; imperforate, flexible main diaphragm means provided in said main control chamber and separating the same into first and second sub-chambers; imperforate, flexible auxiliary diaphragm means provided in said auxiliary control chamber and separating the same into third and fourth subchambers, said first and second sub-chambers being respectively connected to said fourth and third sub-chambers;

said first and second disc members being respectively provided with first and second openings communicating with said first and second sub-chambers, said first and second openings being connected to said first and second outlet ports;

said second and third disc members being respectively provided with third and fourth openings communicating with said third and fourth sub-chambers, said third and fourth openings being connected to said inlet zone;

first and second variable restriction means provided between said main diaphragm means and said first and second openings, said main diaphragm means being responsive to pressure in said first and second sub-chambers to vary the flow restricting effects of said first and second variable restriction means;

third and fourth variable restriction means provided between said auxiliary diaphragm means and said third and fourth openings, said auxiliary diaphragm means being responsive to pressure in said third and fourth sub-chambers to vary the flow restricting effects of said third and fourth variable restriction means, so that rate of flow of fluid through said first and second outlet ports is maintained constant.

orifices.

3. A flow divider according to claim 2, wherein said third and fourth restriction orifices have different diameters.

4. A flow divider according to claim 3, wherein said first and second restriction orifices have different diameters. 

1. A flow divider having at least one inlet zone and first and second outlet ports, comprising: a casing; first, second and third disc members mounted in said casing, said first and second disc members defining a main control chamber, said second and third disc members defining an auxiliary control chamber; imperforate, flexible main diaphragm means provided in said main control chamber and separating the same into first and second sub-chambers; imperforate, flexible auxiliary diaphragm means provided in said auxiliary control chamber and separating the same into third and fourth sub-chambers, said first and second sub-chambers being respectively connected to said fourth and third subchambers; said first and second disc members being respectively provided with first and second openings communicating with said first and second sub-chambers, said first and second openings being connected to said first and second outlet ports; said second and third disc members being respectively provided with third and fourth openings communicAting with said third and fourth sub-chambers, said third and fourth openings being connected to said inlet zone; first and second variable restriction means provided between said main diaphragm means and said first and second openings, said main diaphragm means being responsive to pressure in said first and second sub-chambers to vary the flow restricting effects of said first and second variable restriction means; third and fourth variable restriction means provided between said auxiliary diaphragm means and said third and fourth openings, said auxiliary diaphragm means being responsive to pressure in said third and fourth sub-chambers to vary the flow restricting effects of said third and fourth variable restriction means, so that rate of flow of fluid through said first and second outlet ports is maintained constant.
 2. A flow divider according to claim 1, wherein said first, second, third and fourth openings are first, second, third and fourth restriction orifices; said first and second variable restriction means are annular clearances formed between said main diaphragm means and said first and second restriction orifices; and said third and fourth variable restriction means are annular clearances formed between said auxiliary diaphragm means and said third and fourth restriction orifices.
 3. A flow divider according to claim 2, wherein said third and fourth restriction orifices have different diameters.
 4. A flow divider according to claim 3, wherein said first and second restriction orifices have different diameters. 